Shock tube and cell electroporation device with the shock tube

ABSTRACT

The shock tube comprises a tube, a first electrode, a second electrode and a stopple, wherein the tube is internally provided with a cavity for accommodating a target liquid sample. The first electrode is arranged at one end of the tube. The second electrode is arranged in the stopple, and the outer end of the second electrode can be electrically connected with the exterior via an opening of the stopple. The stopple is internally provided with an elastic piece connected with the second electrode. The outer side of the elastic piece is connected with the stopple, and the inner side of the elastic piece is connected with the second electrode. The invention further provides a cell electroporation device where the shock tube can be placed.

RELATED APPLICATIONS

This application is a national stage entry of International ApplicationNo. PCT/IB2015/059297, filed Dec. 2, 2015, and claims benefit of ChinesePatent Application No. CN201410722470.9, filed Dec. 2, 2014; ChinesePatent Application No. CN201520981250.8, filed Dec. 1, 2015; and ChinesePatent Application No. CN201520981477.2, filed Dec. 1, 2015.

The above applications and all patents, patent applications, articles,books, specifications, other publications, documents, and thingsreferenced herein are hereby incorporated herein in their entirety forall purposes. To the extent of any inconsistency or conflict in thedefinition or use of a term between any of the incorporatedpublications, documents, or things and the text of the present document,the definition or use of the term in the present document shall prevail.

BACKGROUND OF THE INVENTION Field of Invention

The present invention belongs to the technical field of biomedicalinstruments and equipment, and in particular to a shock tube and cellelectroporation device with the shock tube.

Related Art

Cell electroporation (also known as cell electrotransfection or cellelectropermeabilization) is the technology of using electrical pulses tointroduce macromolecules (which cannot penetrate the cell membrane) intocells. Electroporation is a method widely used and strongly recommendedin cell experiments and gene therapy. When applying a strong electricfield, a cell membrane is temporarily turned into permeable nature andmay be penetrable by some foreign materials such as macromolecules. Cellmembrane electroporation effect depends on various parameters of theelectric field, such as pulse type, pulse voltage, pulse duration,number of pulses, and other experimental conditions.

Currently, the devices used for cell electroporation are mainly cellelectroporator, cuvette etc. China's patent No. CN 1965079B discloses anelectroporation device having an elongated hollow member. Theelectroporation device includes an elongated hollow member in order toprovide a uniform electric field in the electroporation process,including in particular the implementation of electroporation byapplying an electric pulse on the two ends of a long hollow member witha pair of electrodes after the hollow member is filled with cells andliquid sample of materials to be injected into cells.

The applicant had applied for US patent for an article entitled “Methodsand devices for electroporation” (application number: US 2013/0052711A1). The patent describes a sample container, herein referred to asshock tube. A shock tube is equivalent to the sample container inaforementioned U.S. patent application. Its function is to fill the tubewith cells and liquid sample of materials to be injected into cells.Upper and lower ends of the shock tube are provided with an upper andlower electrode respectively; connection of the upper and lowerelectrodes to a cell electroporation device forms an electric fieldwithin the shock tube, thereby enabling injection of extracellularmaterials into the cells. After the shock tube is filled with liquidsample, the sample shape is fixed, and the liquid surface will not curvebetween the electrodes as occurred in a traditional open type cuvette.By eliminating the curved liquid surface, electric field inside theliquid becomes more uniform, and electroporation efficiency can beimproved. After the liquid sample is loaded into the shock tube andprior to electroporation, it is necessary to prevent the formation ofair bubbles by residual air which will affect electric currentdistribution. In the patent, the applicant has designed an annulargroove on the tube wall of shock tube which is interconnected with thecavity of shock tube. Experimenters may inject liquid samples into shocktube cavity continuously until after the liquid surface is bulged out ofthe shock tube cavity. The upper electrode covers onto the bulged liquidsurface until the upper edge of shock tube cavity is being pressed, thusforming a seal to the liquid inside the cavity. A small amount ofspilled liquid will flow to the annular groove. This design cangenerally eliminate the presence of residual air in the shock tube whichwill affect the experiment. However, after numerous experiments, theapplicant has found that the above-mentioned patent has relatively highrequirement on manufacturing precision of the shock tube, and therequirement on the operation precision is relatively high too. If themanufacturing is not precise enough, it may easily lead to a bad sealingeffect between the electrode and the upper edge of the cavity. Uptiltingof the electrode may occur after being covered on the cavity, causing itto be separated again from the upper edge of cavity, thereby allowingambient air to enter the cavity again. In addition, if used improperlyby the operator, air bubbles may also be formed easily by residual air,which will affect the efficiency of cell electroporation. Therequirement on reliability of instruments and equipment is very high inscientific research and experiments. Therefore, it is necessary to havesome additional design to improve the reliability of operation.

SUMMARY OF THE INVENTION

In consideration of the above-mentioned problems of the prior art, oneembodiment of the present invention provides a shock tube. The technicalproblems to be solved by one embodiment of the present invention are:

How to improve the sealing performance between the second electrode andend surface of the opening to prevent ambient air from entering thecavity;

How to ensure sealing performance of the shock tube and at the same timeimprove the stability of connection between the second electrode andstopple;

How to reduce the phenomenon of high voltage arc generated in the airoutside the shock tube between two electrodes.

One embodiment of the present invention is directed to theaforementioned problems and provides a cell electroporation device witha shock tube. The technical problem to be solved is: how to improve theperformance of electroporation of the cell electroporation device.

One objective of the shock tube of one embodiment of the presentinvention may be achieved by the following technical solution:

A shock tube, wherein the shock tube comprises a tube, a firstelectrode, a second electrode and a stopple. The tube is internallyprovided with a cavity for accommodating a target liquid sample,characterized in that, the first electrode is arranged at one end of thetube, and the other end of the tube is provided with an openinginterconnected with the cavity. The working part of the first electrodeis interconnected with the cavity. The edge of the opening has anannular end surface. The second electrode is arranged in the stopple,and the outer end of the second electrode can be electrically connectedwith the exterior via an opening of the stopple. The inner end surfaceof the second electrode can be well-matched with the annular end surfaceof the edge of opening. The second electrode and the stopple have anelastic connection in between. The periphery of the opening has apositioning structure which is capable of fixing the stopple at the endof tube and rendering the second electrode under elastic stress.

Its working principle is as follows: During operation, one embodiment ofthe shock tube can be filled up into the cavity with a liquid samplecomprising cells and materials to be injected into the cells, forming abulged liquid surface, then the stopple is secured to the end of tubevia a positioning structure to generate a compressive deformation to theelastic piece between the stopple and the second electrode, while thesecond electrode is pressed against the end surface of the opening, thefirst electrode and second electrode are interconnected with the liquidin the cavity. Then the first electrode and second electrode areconnected with the pulse power supply. Electrification produces anelectric field within the shock tube, causing the cell membranes topossess certain permeability, so that the target material in the liquidsample can enter the cells. When the stopple is fixed to the end portionof the tube, a compressive deformation is generated in the elasticpiece, to avoid the formation of gaps between the second electrode andthe opening, improving the sealing performance between the secondelectrode and the end surface of the opening, thereby preventing airfrom entering the liquid sample in the cavity. In addition, when thestopple becomes slightly uptilted, the elastic piece can also makecertain deformation recovery, to ensure the second electrode to remainclosely abutting with the end surface of opening edge, so that still noair bubble will be generated in liquid sample in the cavity when thereis some operation deviation during sample loading by the experimenter.In summary, the shock tube can effectively improve sealing performancebetween the second electrode and the opening, thus inhibiting ambientair from entering the cavity when loading liquid sample.

The positioning structure of one embodiment of the present applicationdirectly provides stable support and positioning to the outer endportion of elastic piece, so that the elastic piece remains in a stablecompressed state between the stopple and second electrode, enabling theelastic piece to apply a stable elastic force to the second electrode,thus producing a more close and stable matching between the secondelectrode and end surface of the opening of tube, thereby enhancing thesealing effect of the second electrode and end surface of the opening oftube. The positioning structure and elastic piece are inseparable injointly solving the technical problem of “how to enhance the sealingstability between the second electrode and the tube”.

It is worthwhile to note that, one embodiment of the tube and thestopple in the present application are made of an insulating material.The first electrode and second electrode are made of an electricallyconductive material, which is a part of the prior art, and the specificmaterial being used is not the subject of this Specification. Inaddition, the first electrode may either be directly fixed to the tube,or may be installed inside a stopple, as with the second electrode,before being used to seal the cavity of tube.

In one embodiment of the shock tube, the stopple comprises the pipehaving a first through-hole. The second electrode is disposed in thefirst through-hole. The second electrode comprises a rod and a cap. Oneend of the rod is fixedly connected with the cap. The other end of therod can be electrically connected with the exterior via an opening ofthe stopple. The elastic piece is socket-connected on the outer sidesurface of rod. The outer end of the stopple has a retaining edgeradially extended inward along first through-hole. The outer end surfaceof the elastic piece abuts against the retaining edge, and the inner endsurface of the elastic piece abuts against the cap. The elastic piece ismade of rubber and plastic materials. Rubber and plastic materialsinclude plastics, rubber, silicone and the like. When the stopple isfixed to the end portion of the tube, the second electrode iswell-matched with end surface of the edge of opening of tube cavity. Theelastic piece generates a compressive deformation to improve sealingeffect of the second electrode with end surface of the edge of opening.The rod of second electrode can be electrically connected with theexterior via an opening of the retaining edge of the stopple. The rod ofsecond electrode may extend to the exterior of the stopple to allowelectrical connection with the second electrode. The rod may also notextend to the exterior of the stopple. The external electricalconnection contacts may be inserted into the stopple via the opening ofthe stopple to connect to the second electrode. The elastic piece may befabricated generally in a ring shape and may also be a partial ringshape or even other shapes, as long as it is resilient and capable ofbeing plugged with the second electrode. In the shock tube, the elasticpiece may be a separate elastic piece mounted in first through-hole withan interference fit method, or mounted in first through-hole by bondingor other methods and connected with the stopple. The elastic piece maybe socket-connected on the rod of the second electrode with aninterference fit or bonding method.

In one embodiment of the shock tube, a first retaining shoulder isprovided between the elastic piece and the cap. The first retainingshoulder is located between the elastic piece and the cap. The size orthe spatial dimension of the first retaining shoulder is larger than thediameter of rod and smaller than the diameter of cap. The firstretaining shoulder separates the cap from the elastic piece, causing thecap, in compressing the elastic piece, may only apply stress through thefirst retaining shoulder. The diameter or size of first retainingshoulder is smaller than the cap and elastic piece, thereby producingrelatively greater pressure on a small contact area, prompting easydeformation and displacement of elastic piece. When the stopple is fixedin the positioning structure, the second electrode is well-matched withend surface of the opening. The elastic piece is in compressed stateunder pressure from the second electrode. Pressure is generated by thiscompressive deformation and exerted to end surface of opening at end oftube to improve sealing performance, and when the stopple is slightlyuptilted, a certain deformation recovery will be generated to continuepressing the second electrode against the end surface of opening at endof tube.

In one embodiment of the shock tube, the first retaining shoulder may bea separate component, such as a separate ring shape retaining shoulderof size smaller than the elastic piece and the cap. The first retainingshoulder is socket-fitted on the rod between the elastic piece and thecap, and its material may be an insulator or non-insulator.

In one embodiment of the shock tube, as a second case, the firstretaining shoulder is fixedly arranged on the cap, or the firstretaining shoulder forms an integral body with the cap and rod. Theinner end surface of the elastic piece abuts against the end surface ofthe first retaining shoulder. When the rod is plugged the elastic piece,the cap is separated from the elastic piece, and the cap and the elasticpiece mutually exert stresses through the first retaining shoulder.

In one embodiment of the shock tube, as a third case, the firstretaining shoulder is fixedly arranged on the elastic piece, or thefirst retaining shoulder forms an integral body with the elastic piece.The first retaining shoulder abuts against the cap.

In one embodiment of the shock tube, as a solution for an alternativeelastic piece, the connection method of elastic piece with the stoppleis a direct connection. The stopple comprises the pipe having a firstthrough-hole. The second electrode is disposed in the firstthrough-hole. The second electrode comprises a rod and a cap. One end ofthe rod is fixedly connected with the cap. The other end of the rod canbe electrically connected with the exterior via an opening of thestopple. The elastic piece is a resilient retaining edge elastic pieceextended inward along first through-hole on inner wall of the firstthrough-hole. The retaining edge elastic piece abuts against the outerside surface of the rod. The material of retaining edge elastic piece isthe same as the stopple. Its outer side forms an integral body withinner wall of the stopple body, and an opening is formed in its center.The rod of second electrode is plugged to the opening of retaining edgeelastic piece by interference fit or bonding method etc. Due toprecision requirement of the shock tube body, it is generally necessaryto be manufactured with certain strength to prevent deformation. As anelastic piece, the retaining edge elastic piece, which forms an integralbody with the stopple, may use the strength reduction design thereby toachieve flexibility, such as designing a thinner portion than the otherportions, so that it is more prone to generate compressed deformation.The retaining edge elastic piece may generally be made into a ringshape, or it may not be in ring shape, as long as it is flexible and canbe plugged with the second electrode.

In one embodiment of the shock tube, as a first case, a second retainingshoulder is provided between the retaining edge elastic piece and thecap. The size or spatial dimension of the second retaining shoulder islarger than the diameter of rod and smaller than the diameter of cap.The second retaining shoulder may be a separate retaining ring.

In one embodiment of the shock tube, as a second case, the secondretaining shoulder is fixedly arranged on the cap or the secondretaining shoulder forms an integral body with the cap and rod. Theinner end surface of the retaining edge elastic piece abuts against theend surface of the second retaining shoulder.

In one embodiment of the shock tube, as a third case, the secondretaining shoulder is fixedly arranged on the retaining edge elasticpiece or the second retaining shoulder forms an integral body with theretaining edge elastic piece. The second retaining shoulder abutsagainst the cap.

In one embodiment of the shock tube, as a solution for third type ofelastic piece, the elastic piece is a compression spring. The stopplecomprises a pipe having a first through-hole. The second electrode isdisposed in the first through-hole. The second electrode comprises a rodand a cap. One end of the rod is fixedly connected with the cap. Theother end of the rod can be electrically connected with the exterior viaan opening of the stopple. The compression spring is socket-connected onthe outer side surface of the rod. The outer end of the stopple has aretaining edge radially extended inward along the first through-hole.The outer end surface of the compression spring abuts against theretaining edge, and the inner end surface of the compression springabuts against the cap. When the stopple is fixed to the end part oftube, the compression spring can generate a deformation compression toimprove the sealing performance between the second electrode and the endpart of tube at the edge of opening.

In one embodiment of the shock tube, the positioning structure comprisesa connecting tube which forms an integral body with the end part of thetube. The connecting tube is provided with a chamber for the stopple toplugin. The chamber wall of the chamber has a first rib. The outer sidesurface of the stopple has a second rib which can snap-connect withfirst rib. The first rib and second rib may be of a complete annularshape or discontinuous annular shape or even non-annular shape. Asnap-connection effect can be achieved in all cases. The protrusions offirst rib and second rib may not be obvious. A stopple of size slightlylarger than the internal size of the connecting tube is used to insertinto the tube portion, to achieve the purpose of positioning byinterference fit method. The stopple is snap-connected with theconnecting tube, making both connection and separation of the two veryeasy, to enhance the convenience in liquid injection and pipetting afterthe completion of electroporation. Of course the threaded connectionmethod may also be used. While using threaded connection, the stopplecan be fixed to the connecting tube by rotating it.

In one embodiment of the shock tube, the positioning structure comprisesa first strike disposed on the stopple. The tube is provided with afirst latch which can snap-connect with the first strike.

In one embodiment of the shock tube, the end surface of the edge ofopening is provided with an annular groove. During operation, the shocktube can be filled up into the cavity with a liquid sample until theliquid sample has formed a bulged surface on the opening, and then thesecond electrode is in contact with the bulged liquid surface, andpresses downward to seal the opening to ensure that no residual air isinside the cavity. The excess liquid needed in forming the bulgedsurface will overflow into the annular groove, without affecting thecell electroporation process in liquid sample in the cavity.

In one embodiment of the shock tube, the stopple and the tube isconnected by a flexible link. The two ends of the flexible link areconnected with the stopple and tube respectively, so that the stopple isconnected with the tube but also able to swing in relative to the tube,avoid accidental loss of the stopple. The plastic material of theflexible link is fabricated relatively thin so as to achieve theflexibility of large angle bending.

In one embodiment of the shock tube, outer side of the elastic piece andthe stopple are well-matched and form a seal. Inner side of the elasticpiece and outer side surface of the second electrode are well-matchedand form a seal.

In one embodiment of the shock tube, the cavity of tube is provided withan ion conductive layer. The bottom layer surface of the ion conductivelayer is in contact with a first electrode. The upper layer surface ofthe ion conductive layer is capable of contacting with the target liquidsample. This design separates the cell sample from direct contact withthe first electrode, so as to avoid direct damage to the cell sample byelectrochemical reaction near the first electrode. The ion conductivelayer contains components of a soluble salt as the ion source, and maycontain gel substance such as agarose, agar, polyacrylamide, colloidalprotein etc. to form a gel or semi-solid state, or may contain poroussolids infiltratable by the salt solution to form a state capable ofion-conduction state.

A further objective of the shock tube of one embodiment of the presentinvention may be achieved by the following technical solution:

A shock tube, wherein the shock tube comprises a tube and a stopple. Thetube is internally provided with a cavity for accommodating a targetliquid sample. The first electrode interconnected with the cavity isarranged at one end or middle part of the tube, and the other end of thetube is provided with an opening interconnected with the cavity. Thesecond electrode is arranged in the stopple, and the second electrodecomprises a rod and a cap. One end surface of the cap can bewell-matched with the annular end surface of the edge of opening. Anelastic connection is provided between the second electrode and thestopple, characterized in that, the rod is inserted into the stopple andslidably connected to the stopple. A limiting structure is furtherprovided between the second electrode and the stopple to preventseparation of the rod from the stopple.

Its working principle is as follows: During operation, one embodiment ofthe shock tube can be filled up into the cavity from opening of tubewith a liquid sample comprising cells and materials to be injected intothe cells, then the stopple is secured to the end of tube. Outer endsurface of the cap of second electrode is well-matched with the annularend surface at the edge of tube opening. One end of the first electrodeand second electrode are interconnected with the liquid in the cavity,and the other ends of first electrode and second electrode can beelectrically connected with the exterior, so the first electrode andsecond electrode are connected with the pulse power supply.Electrification produces an electric field within the cavity of shocktube, causing the cell membranes to possess certain permeability, sothat the target material in the liquid sample can enter the cells. Inthe present technical solution, when the stopple is fixed to the endportion of the tube, the elastic piece is positioned between the stoppleand the cap of second electrode, and capable of forming a seal betweenthe cap and the stopple. The rod of second electrode is plugged to thestopple and slidably connected to the stopple, and capable ofeffectively preventing the second electrode from falling off the stopplevia a limiting structure.

In one embodiment of the shock tube, the limiting structure comprises arim extended from outer end of the rod along the radial direction of therod. Radial size of the rim is slightly larger than the diameter of theopening of the stopple. The rim is capable of pressing the stopple,under external force, to generate a deformation and passes out of theopening. After the stopple is deformed under external compression, therim can pass smoothly through the stopple. After the stopple hasrecovered from the deformation, the rim can maintain the limitation withthe stopple, effectively preventing the second electrode from fallingoff.

In one embodiment of the shock tube, opening part of the stopple has anabutment surface abutting against the rim. After the stopple is deformedunder external compression, the rim can pass smoothly through thestopple and maintain the limitation by matching with the abutmentsurface to prevent the second electrode from falling off.

In one embodiment of the shock tube, the rim is cone shape. Outer sidesurface of the rim has a first guiding surface obliquely extendedtowards outer side surface from end surface of rim. Through the guidingeffect of first guiding surface, it is possible to facilitate theinstallation and placement of the second electrode.

In one embodiment of the shock tube, the stopple comprises a pipe havinga first through-hole. The rod is inserted into the first through-hole.The limiting structure comprises an annular bulge on inner side wall ofpipe. The cap is disk shape, and outer diameter of the cap is largerthan inner diameter of the annular bulge. The cap can pass through theannular bulge in such a way that the outer end surface of cap is abovethe upper side surface of the annular bulge. As a solution ofalternative limiting structure, after the annular bulge on pipe isdeformed under external compression, the cap can pass smoothly throughthe inner hole of annular bulge. After the annular bulge has recoveredfrom the deformation, the outer end surface of cap abuts against theupper side surface of annular bulge and maintains the limitation,effectively preventing the second electrode from falling off.

In one embodiment of the shock tube, the height of pipe of the stoppleis greater than height of the elastic piece. So the elastic piece ispositioned within the pipe, and the cap of second electrode is alsopositioned within the pipe. A limiting effect is applied to secondelectrode and elastic piece through the pipe, and further, also enablesthe cap of second electrode and inner wall of pipe to form a seal, so asto improve sealing performance.

In one embodiment of the shock tube, the pipe is provided with a tubularmounting seat. The second electrode is slidably connected on themounting seat. The elastic piece is socket-fitted on the mounting seat.The height of the elastic piece is greater than the height of mountingseat. When the stopple is fixed to the end portion of tube, the elasticpiece generates a compressive deformation, causing upper end surface ofelastic piece abuts against the stopple and lower end surface of elasticpiece abuts against upper end surface of the cap. The elastic piece ispositioned between the pipe of the stopple and the mounting seat, andboth ends of the elastic piece abut against the stopple and secondelectrode respectively. The elastic piece generates compressivedeformation, so that the elastic piece forms a seal with the stopple andsecond electrode, preventing occurrence of gaps between the secondelectrode and the opening of tube, and inhibiting air from entering theliquid sample in cavity. Further, when the stopple becomes slightlyuptilted, the elastic piece can also make certain deformation recovery,to ensure the second electrode to remain closely abutting with the endsurface of opening edge, so that still no air bubble will be generatedin liquid sample in the cavity when there is some operational deviationduring sample loading by the experimenter. In summary, the technicalsolution can effectively improve sealing performance between secondelectrode and opening, thus inhibiting ambient air from entering thecavity when loading liquid sample.

Since the elastic piece is positioned between the pipe of the stoppleand mounting seat, and its upper and lower ends abut against the stoppleand second electrode respectively, the elastic piece will not fall off.Meanwhile the elastic piece may perform limitation to the cap of secondelectrode to prevent excessive movement of the second electrode.

In one embodiment of the present technical solution, the tube andstopple are made of an insulating material. The first electrode andsecond electrode are made of an electrically conductive material, whichis a part of the prior art, and the specific material being used is notthe subject of this Specification. In addition, the first electrode mayeither be directly fixed to the tube, or may be installed inside astopple, as with the second electrode, before being used to seal thecavity of tube.

In one embodiment of the shock tube, the inner side wall of the mountingseat is provided with a third guiding surface obliquely extended toinner side wall from end surface of the mounting seat. Through theguiding effect of third guiding surface, it is possible to facilitatethe installation and placement of the second electrode.

In one embodiment of the shock tube, there is a gap between outer sidesurface of the elastic piece and inner side wall of the pipe of thestopple. The retaining of this gap can provide a certain amount of spacefor deformation of elastic piece, so that the automatic adjustment ofgap sealing between the stopple and second electrode is achieved byusing the recovery force of elastic piece.

In one embodiment of the shock tube, the stopple comprises a pipe havinga first through-hole. The rod is inserted into the first through-hole.The pipe is provided with a tubular mounting seat inside. The secondelectrode is slidably connected on the mounting seat. The elastic pieceis the resilient part at lower end of the mounting seat. The joint ofthe rod and cap is provided with a slope abutting against the endsurface of the elastic piece. The rod has a slope for inserting intomounting seat. After the slope is inserted into the mounting seat, theelastic piece on the mounting seat is elastically deformed to improvesealing performance.

In one embodiment of the shock tube, the periphery of the opening has apositioning structure which is capable of fixing the stopple at the endof tube and generating a compressive deformation to the elastic piece.Through the positioning structure, the elastic piece is deformed tofurther improve the sealing performance, while effectively preventingthe stopple from falling off the end of tube.

In one embodiment of the shock tube, the positioning structure comprisesa connecting tube which forms an integral body with the end part of thetube. The connecting tube is provided with a chamber for the stopple toplugin. The chamber wall of the chamber has a first rib. The outer sidesurface of the stopple has a second rib which can snap-connect with thefirst rib. The first rib and second rib may be of a complete annularshape or discontinuous annular shape or even non-annular shape. Asnap-connection effect can be achieved in all cases. The protrusions offirst rib and second rib may not be obvious. A stopple of size slightlylarger than the internal size of connecting tube is used to insert intothe tube portion, to achieve the purpose of positioning by interferencefit method. The stopple is snap-connected with the connecting tube,making both connection and separation of the two very easy, to improvethe convenience in liquid injection and pipetting after the completionof electroporation. Of course the threaded connection method may also beused. While using threaded connection, the stopple can be fixed to theconnecting tube by rotating it.

In one embodiment of the shock tube, as an alternative solution, thepositioning structure comprises a first strike disposed on the stopple.The tube is provided with a first latch which can snap-connect with thefirst strike.

In one embodiment of the shock tube, the end surface at edge of theopening has an annular groove. The stopple and the tube are connected bya flexible link. The two ends of the flexible link are connected withthe stopple and tube respectively, so that the stopple is connected withthe tube but also able to swing in relative to the tube, to avoidaccidental loss of the stopple. The plastic material of the flexiblelink is fabricated with a relatively thin. It can achieve theflexibility of large angle bending. This will not interfere with theremoval of the stopple from the tube, and it can also prevent loss ofthe stopple from falling off. It is very convenient to use.

A further objective of shock tube of one embodiment of the presentinvention may be achieved by the following technical solution:

A shock tube, wherein the shock tube comprises a stopple and anintegrally fabricated tube. The tube is internally provided with acavity for accommodating a target liquid sample. One end of the tube isprovided with an opening interconnected with the cavity. A secondelectrode is arranged in the stopple, and the outer end of the secondelectrode can be electrically connected with the exterior via an openingof the stopple. The inner end surface of the second electrode can bewell-matched with the annular end surface of the edge of opening,characterized in that, a first electrode interconnected with cavity isarranged at middle of the tube. The first electrode forms a seal withthe tube. The part of tube below first electrode is the extensionsegment, which is capable of preventing the first electrode and secondelectrode from generating a high voltage arc on the outer side of thetube.

Its working principle is as follows: During operation, one embodiment ofthe shock tube can be filled up into the cavity from opening of tubewith a liquid sample comprising cells and materials to be injected intothe cells, then the stopple is secured to the end of tube making innerend surface of second electrode well-matched with the annular endsurface at the edge of tube opening. Both first electrode and secondelectrode are interconnected with the liquid in the cavity. Theelectrode terminal may extend through the extension segment of the tubeand electrically connected with the first electrode. The outer end ofthe second electrode can be electrically connected with the exterior viaan opening of the stopple. The outer ends of the first electrode andsecond electrode are connected with the pulse power supply.Electrification produces an electric field within the cavity of shocktube, causing the cell membranes to possess certain permeability, sothat the target material in the liquid sample can enter the cells. Inthe present technical solution, the part of tube below first electrodeis the extension segment, which is capable of preventing the firstelectrode and second electrode from generating a high voltage arc on theouter side of the tube. The extension segment has good insulationperformance, and generally does not breakdown under pulse voltage. Thefirst electrode and second electrode will have to bypass the extensionsegment to produce a high voltage outside the tube. The air breakdowndistance between the first electrode and second electrode is extendedgreatly by the addition of extension segment. Even if a very highvoltage is applied, it can effectively prevent the breakdown betweenfirst electrode and second electrode in the ambient air of tube, therebyensuring the current to achieve electroporation to the target liquidsample in cavity.

In addition, one embodiment of the extension segment is serving as ahandle too, for convenient handling of the shock tube by users.

In one embodiment of the present technical solution, the tube andstopple are made of an insulating material. The first electrode andsecond electrode are made of an electrically conductive material, whichis a part of the prior art, and the specific material being used is notthe subject of this Specification. In addition, the first electrode mayeither be directly fixed to the tube, or may be installed inside astopple, as with the second electrode, before being used to seal thecavity of tube.

In one embodiment of the shock tube, the length of the extension segmentis generally between 1 mm and 40 mm, based on needs. Preferably, thelength of the extension segment may be between 2 mm and 30 mm. Morecommonly, it is between 5 mm and 20 mm. When the length of extensionsegment is greater than the length of cavity, the air breakdown pathdistance between the first electrode and second electrode outside thetube is at least three times the length of cavity. Hence the firstelectrode and second electrode are almost impossible to produce a highvoltage arc outside the tube.

In one embodiment of the shock tube, the tube is made of a plasticmaterial. The wall thickness of tube in extension segment is smallerthan the wall thickness of tube in the cavity. The wall thickness oftube in the cavity is relatively larger to prevent the high voltagebreakdown between the first electrode and the second electrode. In themeantime, the wall thickness of tube in extension segment is less thanthe wall thickness of tube in the cavity to facilitate the insertion offirst electrode from the extension segment into the tube and installedin the middle of the tube, and also facilitates the insertion ofelectrode terminal into the extension segment of tube to have electricalconnection with the first electrode.

In one embodiment of the shock tube, the interior diameter of the tubein extension segment is greater than the interior diameter of the tubein the cavity and forms a step in the tube. The first electrode has aflange and a peg located at upper side of flange. The end surface of theflange is in contact with the step. The peg is snap-connected in thetube hole of the cavity. The step and flange coordinate with each otherto play a role in positioning limitation to improve ease of installationwhile ensuring sealing performance and to prevent leakage of targetliquid sample.

In one embodiment of the shock tube, a contact part is disposed at lowerside of flange of the first electrode. The diameter of the contact partis smaller than diameter of flange, and there is a gap between thecontact part and tube wall of extension segment of the tube. The contactpart can also facilitate the handling, placement and installation of thesecond electrode.

In one embodiment of the shock tube, the length of the contact part isusually short, to prevent too close a distance from first electrode tolower end of extension segment, which may, bypassing the extensionsegment, induce voltage arc.

In one embodiment of the shock tube, the stopple is internally providedwith an elastic piece connected with the second electrode. The outerside of the elastic piece is connected with the stopple, and the innerside of the elastic piece is connected with the second electrode. Whenthe stopple is fixed to the end portion of the tube, the elastic piecegenerates a compressive deformation, so that the elastic piece forms aseal with the stopple and second electrode, preventing occurrence ofgaps between the second electrode and the opening of tube, andinhibiting air from entering the liquid sample in cavity. Further, whenthe stopple becomes slightly uptilted, the elastic piece can also makecertain deformation recovery, to ensure the second electrode to remainclosely abutting against the end surface of opening edge, so that stillno air bubble will be generated in liquid sample in the cavity whenthere is some operation deviation during sample loading by theexperimenter. In summary, the present technical solution can effectivelyimprove sealing performance between second electrode and opening,thereby inhibiting ambient air from entering the cavity when loadingliquid sample.

In one embodiment of the shock tube, the stopple comprises the pipehaving a first through-hole. The second electrode is disposed in thefirst through-hole. The second electrode comprises a rod and a cap. Oneend of the rod is fixedly connected with the cap. The other end of therod can be electrically connected with the exterior via an opening ofthe stopple. The elastic piece is socket-connected on the outer sidesurface of rod. The outer end of the stopple has a retaining edgeradially extended inward along first through-hole. The outer end surfaceof the elastic piece abuts against the retaining edge, and the inner endsurface of the elastic piece abuts against the cap. The elastic piece ismade of rubber and plastic materials. Rubber and plastic materialsinclude plastics, rubber, silicone and the like. When the stopple isfixed to the end portion of the tube, the second electrode iswell-matched with end surface of the edge of opening of tube cavity. Theelastic piece generates a compressive deformation to improve sealingeffect of the second electrode with end surface of the edge of opening.The rod of second electrode can be electrically connected with theexterior via an opening of the stopple retaining edge. The rod of secondelectrode may extend to the exterior of the stopple to allow electricalconnection with the second electrode. Of course the rod may also notextend to the exterior of the stopple, and instead the externalelectrical connection contacts is inserted into the stopple via stoppleopening to be connected to the second electrode. The elastic piece maybe formed generally into ring shape, and may be a partial ring shape oreven other shapes, as long as it is resilient and capable of beingplugged with the second electrode. The elastic piece may be a separateelastic piece mounted in first through-hole with an interference fitmethod, or mounted in first through-hole by bonding or other methods andconnected with the stopple.

In one embodiment of the shock tube, as an alternative solution, thestopple comprises a pipe having a first through-hole and a tubularmounting seat located in the pipe. The second electrode is slidablyconnected on the mounting seat and an annular elastic piece issocket-fitted outside the mounting seat. The height of elastic piece isgreater than the height of mounting seat. The second electrode comprisesa rod and a cap. Inner end of the rod is fixedly connected with the cap.The outer end of the rod can be electrically connected with the exteriorvia an opening of the stopple. The outer end of the rod has a rimradially extended along the rod. The size of the rim is slightly largerthan the opening of the stopple. Opening part of the stopple has anabutment surface abutting against the rim. The elastic piece ispositioned between the pipe and the mounting seat. When the stopple isfixed to the end portion of the tube, a compressive deformation isgenerated by the elastic piece, causing the outer end surface of theelastic piece abutting against the stopple, and the inner end surface ofelastic piece abuts against the cap. The elastic piece is positionedbetween the pipe of the stopple and mounting seat, and will not falloff. In addition, as long as the stopple and second electrode abutagainst the two ends of elastic piece respectively, a seal is achieved.While installation is facilitated, sealing performance is also ensured.

In one embodiment of the shock tube, the elastic piece is socket-fittedon outer side surface of the mounting seat, and inner side surface ofthe elastic piece is in contact with outer side surface of the mountingseat. The inner side surface and upper end surface of elastic piece isin contact and abuts against the stopple, forming a multi-surfacesealing connection, which, in addition to the sealing connection formedbetween inner end surface of elastic piece and the second electrode,further improve the sealing performance.

In one embodiment of the above technical solutions, the first electrodeis multi-segmentally cylindrical or conical in shape. The outer sidewall at upper end of first electrode has an annular band along thecircumference of the first electrode. The annular band forms awell-matched seal with the inner wall of the cavity. The outer sidesurface of the flange and the tube wall of extension segment may beallowed some gaps for easy installation. The formation of seal by localannular band and inner wall of the cavity can facilitate installationand reducing resistance when the first electrode is placed. The lengthof extension segment in the present technical solution is ⅓ ˜⅔ of thetotal length of tube.

The objectives of one embodiment of the cell electroporation device withthe shock tube of present invention can be achieved by the followingtechnical solutions:

A cell electroporation device with a shock tube, wherein the cellelectroporation device comprises a housing. The housing is disposed witha fixing base. The fixing base is provided with a socket. Characterizedin that, the cell electroporation device also comprises a shock tubewhich can be plugged in the socket. The shock tube comprises a tube, afirst electrode, a second electrode and a stopple, wherein the tube isinternally provided with a cavity for accommodating a target liquidsample. The first electrode is arranged at one end of the tube, and theother end of tube is provided with an opening interconnected with thecavity. The working part of the first electrode is interconnected withthe cavity. The edge of the opening has an annular end surface. Thesecond electrode is arranged in the stopple, and the outer end of thesecond electrode can be electrically connected with the exterior via anopening of the stopple. The inner end surface of the second electrodecan be well-matched with the annular end surface of the edge of opening.The stopple is internally provided with an elastic piece connected withthe second electrode. The outer side surface of the elastic piece isconnected with the stopple, and the inner side of the elastic piece isconnected with the second electrode. The periphery of opening has apositioning structure which is capable of fixing the stopple at the endportion of tube generating a compressive deformation to the elasticpiece. The inner end of the socket has a first electrode terminal whichcan be electrically connected to the first electrode. The housing isprovided with a cover for covering the outer end of socket. The cover isdisposed with a second electrode terminal which can be electricallyconnected with the second electrode. The housing is also provided with apower module which is electrically connected to the first electrodeterminal and second electrode terminal.

Its working principle is as follows: During operation, one embodiment ofthe cell electroporation device can be filled up into the tube cavitywith a liquid sample and then covered with stopple. After the shock tubeis placed in the socket, the cover is closed, so the first electrodeterminal is electrically connected to the first electrode, and thesecond electrode terminal is electrically connected to the secondelectrode, and the pulse power is turned on to supply electricity,forming an electric field within the shock tube, enabling the injectionof extracellular substances into the cells. Preferably, the shock tubeis arranged vertically, and the two electrodes of shock tube are set inupper and lower positions respectively. The first electrode terminal andsecond electrode terminal are correspondingly disposed above and beneaththe shock tube respectively.

Since one embodiment of the stopple is also provided with an elasticpiece for enhancing the action force between the second electrode andthe end surface of opening, thus inhibiting gaps to occur between thesecond electrode and the opening. In addition, when the stopple becomesslightly uptilted, the elastic piece can also make certain deformationrecovery, to ensure the second electrode to remain closely abutting withthe end portion of tube at end surface of opening, thus inhibitingambient air from entering the cavity. Meanwhile, the internal generationof gas bubbles by electrochemical reaction in the shock tube duringelectroporation process can also be restrained. In summary, the shocktube of the cell electroporation device can effectively improve sealingperformance between the second electrode and the end surface of opening,thus inhibiting ambient air from entering the cavity and forming airbubbles during the electroporation preparation process. Since airbubbles are basically non-conductive, the electric current can only flowthrough the gap between air bubbles, resulting in a strong electriccurrent in the gaps of air bubbles, causing the cells to die easily. Theelectric current before and after the air bubbles (relative to the maincurrent flow direction) is weak, causing difficulty in cellelectroporation, thus affecting the electrotransfection. The shock tubedevice of present invention has reduced the influence of gas bubbles,which is generated by electrochemical reaction, on electric currentduring the electroporation process, thereby improving theelectroporation performance of the cell electroporation device.

In one embodiment of the cell electroporation device with the shocktube, the fixing base comprises a seat and a clamping cylinder. Thesocket is disposed inside the clamping cylinder. A silo is provided inthe seat. The clamping cylinder is inserted in the silo and both aredetachable and interconnectable with each other. Since the clampingcylinder and silo are detachable and can be interconnected with eachother, the clamping cylinder with corresponding size of socket diametercan be replaced, depending on different diameter size of the shock tube,thus increasing versatility of this cell electroporation device.

In one embodiment of the cell electroporation device with the shocktube, the clamping cylinder is made of a material with lighttransmittance greater than 50%.

In one embodiment of the cell electroporation device with the shocktube, the bottom of the clamping cylinder abuts with the bottom of thesilo. The top end of clamping cylinder is provided with at least onehandle. With handle provided in the design, assembly and disassembly ofclamping cylinder is more convenient for the operator. To accommodateshorter shock tubes, a metal electrode extension piece can also bemounted at the bottom of the clamping cylinder. The bottom part of metalextension piece is in contact with first electrode terminal. Electricalconnection is made through the metal extension piece between firstelectrode and first electrode terminal, when a shorter shock tube isinserted into the clamping cylinder, and the height deficiency of shocktube is compensated in this manner.

In one embodiment of the cell electroporation device with the shocktube, the seat contains also a hollow. The silo has a secondthrough-hole at its bottom. The two ends of the second through-hole areconnected with the socket and hollow respectively. The hollow isprovided with a spring seat and a spring. The inner end of the spring isfixed on the spring seat, and the outer end of the spring is connectedto the inner end of the first electrode terminal. The outer end of thefirst electrode terminal can pass through the second through-hole andinserts in the socket. After the spring seat and spring are provided inthe design, when the socket opening is closed by the cover, the firstelectrode and second electrode can be connected to the first electrodeterminal and second electrode terminal respectively. When the shock tubeis pressed by the cover, the spring is compressed and a greater extrapressure is generated. This pressure is exerted through a secondelectrode to the opening of cavity, enhancing the sealing performance ofsecond electrode and opening of cavity. During the cell electroporationprocess, due to the electrochemical reaction, the electrolysis processwill produce some air or gas bubbles. When gas bubble pressure isgenerated between the second electrode and the opening of cavity, thepressure produced by the spring can be exerted to the cell sample tocounter the gas bubble pressure. These electrochemical gas bubbles willbe compressed and its influence to the distribution of electric currentin the electroporation process will be reduced, thereby increasing cellelectroporation effect. In general, the pressure requirement for commonspring to provide electrical contact point pressure is not much,especially when the voltage is as high as several hundred volts tothousand volts or even higher. A low pressure such as a load of lessthan 1 N (Newton) is sufficient to provide proper electrical connection.Unlike a common spring for electrical contacts, the function of springin the cell electroporation device of present invention is not only toprovide pressure for electrical contacts, but also required to generatea greater additional pressure to counter electrolytic air bubblepressure. The higher pressure here generally refers to a stress over 1N, or above 2 N, or higher than 4 N, or even higher after the spring iscompressed. After the completion of cell electroporation, when the coveris opened, the shock tube may pop up partially from the socket under theaction of spring, making it convenient to pick it up.

In one embodiment of the cell electroporation device with the shocktube, the cover is made of a material with light transmittance greaterthan 50%. The seat accessory is provided with a sensor for detecting thedisplacement change of shock tube. The housing is internally providedwith a micro control unit electrically connected with the sensor. Thehousing is also provided with an indicator lamp. The indicator lamp isconnected with the power module. Signals of the sensor can betransmitted to the micro control unit for controlling the indicatorlamp. In addition to the function of indicating the connection status ofshock tube, it can also serve the function of illumination. A brighterindicator lamp such as LED light can be used to illuminate the shocktube. The sensor can be a mechanical trigger switch. The switch will betriggered by its linkage bar when displacement of first electrodeterminal occurs. The sensor can also be a photoelectric switch. Thephotoelectric switch will be triggered by an impacted optical path whendisplacement of first electrode terminal occurs. The sensor can also bea Hall switch etc., triggered when displacement of the shock tube orfirst electrode terminal occurs.

In one embodiment of the cell electroporation device with the shocktube, the indicator lamp can be mounted on housing near the shock tubesocket, providing lights to illuminate the shock tube nearby. Theindicator lamp can also be mounted on the fixing base. A transversethrough-hole may be provided on the fixing base to install the indicatorlamp. The clamping cylinder may be made of a transparent material. Theindicator lamp on the fixing base may be used to illuminate the shocktube laterally through the clamping cylinder, achieving a clearer visualeffect. Also, transparent clamping cylinders of different sizes canaccommodate shock tubes of different sizes.

In one embodiment of the cell electroporation device with the shocktube, the housing is provided with a display screen. The housing isprovided with a sampler. The micro control unit is connected withdisplay screen and power module. The sampler is connected with shocktube and micro control unit respectively. Electrical signal collected bythe sampler can be transmitted to a micro control unit and displays inthe form of wave curves on the display screen. A power supply module cangenerate electric pulses required in cell electroporation. The housingis provided with a display screen for displaying instrumental andexperimental information as well as displaying the experiment operationinterface. The micro control unit in housing can control the powermodule and display screen. The micro control unit includes aprogrammable microcomputer and other microprocessors etc. The samplercan collect electrical signals in cell electroporation process,including voltage or current signals. The sampler includes resistors andother electronic components. Electrical signals are being processed viathe micro control unit, and can be displayed in the form of wave curveson the display screen.

In one embodiment of the cell electroporation device with the shocktube, inner end of the cover is hinged to the housing. Outer end of thecover is provided with a second latch. The housing is also provided witha second strike which can snap-connect with the second latch. One end ofcover is hinged to the housing, and the other end is snap-connected withthe housing to facilitate the opening and closing of cover.

Compared with the prior art, one embodiment of the present invention hasthe following advantages:

1. When the stopple is fixed to the end portion of the tube, acompressive deformation is generated by the elastic piece, to avoid theformation of gaps between the second electrode and the opening,improving the sealing performance between the second electrode and theend surface of the opening, thereby preventing air from entering theliquid sample in the cavity. In addition, when the stopple becomesslightly uptilted, the elastic piece can also make certain deformationrecovery, to ensure the second electrode to remain closely abutting withthe end surface of opening edge, so that still no air bubble will begenerated in liquid sample in the cavity when there is some operationdeviation during sample loading by the experimenter. In summary, theshock tube can effectively improve sealing performance between thesecond electrode and the opening, thus inhibiting ambient air fromentering the cavity when loading liquid sample.

2. The part of tube below first electrode is the extension segment,which is capable of preventing the first electrode and second electrodefrom generating a high voltage arc on the outer side of the tube. Theextension segment has good insulation performance. The first electrodeand second electrode will have to bypass the extension segment toproduce a high voltage arc on the outer side of the tube. The airbreakdown distance between the first electrode and second electrode isextended greatly by the provision of extension segment. Even if a veryhigh voltage is applied, it can effectively prevent the breakdownbetween first electrode and second electrode in the ambient air on outerside of tube, thus ensuring the electric pulse to achieveelectroporation to the target liquid sample in cavity.

3. The rod of second electrode is inserted into the stopple and slidablyconnected to the stopple, and capable of effectively preventing thesecond electrode from falling off the stopple via a limiting structure.

4. When the shock tube is pressed by the cover of cell electroporationdevice of the present invention, an extra pressure is generated. Thispressure is exerted through a second electrode to the end of tube at theedge of opening, enhancing the sealing performance of second electrodeand the edge of opening, enabling the compression of electrochemical airbubbles generated by electrochemical reaction in the solution to acertain extent during the cell electroporation process, thereby reducingits influence to the distribution of electric current in theelectroporation process and increase the cell electroporation effect.

5. The cell electroporation device of present invention enables theexperimenter to observe the state of shock tube, helping theexperimenter to observe and control the progress of experiments.

6. The cell electroporation device of present invention can display theactual current or voltage waveform in cell electroporation process tofacilitate the experimenter to observe and control the progress ofexperiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural diagram of one embodiment of a shock tube priorto the installation of a second electrode in embodiment 1.

FIG. 2 is a cross-sectional diagram of one embodiment of a shock tubeprior to the fixing of a stopple in a positioning structure inembodiment 1.

FIG. 3 is a partial enlargement diagram of embodiment 1.

FIG. 4 is a partial enlargement diagram of embodiment 2.

FIG. 5 is a partial enlargement diagram of embodiment 3.

FIG. 6 is a cross-sectional diagram of one embodiment of a shock tubewhen a second electrode together with a stopple is fixed in apositioning structure.

FIG. 7 is a partial enlargement diagram of embodiment 4.

FIG. 8 is a partial enlargement diagram of embodiment 5.

FIG. 9 is a partial enlargement diagram of embodiment 6.

FIG. 10 is a partial enlargement diagram of embodiment 7.

FIG. 11 is a structural diagram of one embodiment of a cellelectroporation device in embodiment 8.

FIG. 12 is a partial enlargement diagram of embodiment 11.

FIG. 13 is an exploded diagram of one embodiment of a cellelectroporation device in embodiment 8.

FIG. 14 is a working principle diagram of one embodiment of a cellelectroporation device in embodiment 8.

FIG. 15 is an axonometric diagram of one embodiment of a cellelectroporation device in embodiment 8.

FIG. 16 is a cross-sectional diagram of one embodiment of a shock tubewhen, together with a stopple, a second electrode is fixed in apositioning structure in embodiment 9.

FIG. 17 is a partial enlargement diagram of embodiment 9.

FIG. 18 is a partial enlargement diagram of embodiment 10.

FIG. 19 is a partial enlargement diagram of embodiment 11.

FIG. 20 is cross-sectional diagram of one embodiment of a shock tubewhen, together with a stopple, a second electrode is fixed inpositioning structure in embodiment 12.

DETAILED DESCRIPTION OF THE INVENTION

By the following specific embodiments and accompanied figures, thetechnical solution of present invention will be more specificallydescribed, but the present invention is not limited to theseembodiments.

Embodiment 1

As shown in FIGS. 1, 2, 3, and 6, one embodiment of the shock tubecomprises a tube 1, a first electrode 2, a second electrode 3 and astopple 4. The stopple 4 and the tube 1 are connected by a flexible link30. The tube 1 is internally provided with a cavity 1 e foraccommodating a target liquid sample. The first electrode 2 is arrangedat one end of tube 1, and the other end of tube 1 is provided with anopening 1 a interconnected with the cavity 1 e. The working part of thefirst electrode 2 is interconnected with the cavity 1 e. The edge of theopening 1 a has an annular end surface. The second electrode 3 isarranged in the stopple 4, and the outer end of the second electrode 3can be electrically connected with the exterior via an opening of thestopple 4. The inner end surface of the second electrode 3 can bewell-matched with the annular end surface on the edge of opening 1 a. Anelastic piece is disposed between the stopple 4 and second electrode 3.The outer side surface of the elastic piece is abutting against orconnected with the stopple 4, and the inner side surface of the elasticpiece is abutting against the second electrode 3. The periphery of theopening 1 a has a positioning structure which is capable of fixing thestopple 4 at the end of tube 1 and generating a compressive deformationto the elastic piece. The positioning structure comprises a connectingtube 1 b which forms an integral body with the end part of the tube 1.The connecting tube 1 b is provided with a chamber 1 c for the stopple 4to plug-in. The chamber wall of the chamber 1 c has a first rib 1 d. Theouter side surface of the stopple 4 has a second rib 43 which cansnap-connect with first rib 1 d. In the present embodiment, the firstrib 1 d and second rib 43 are in complete annular shapes. They may alsobe in other shapes composed of several arcuate segments etc.

During operation, one embodiment of the shock tube can be filled up intothe cavity 1 e with a liquid sample comprising cells and materials to beinjected into the cells, forming a bulged liquid surface, then thestopple 4 is secured to the end of tube 1 via a positioning structure togenerate a compressive deformation to the elastic piece between thestopple 4 and the second electrode 3, while the second electrode 3 ispressed against the end surface of the opening 1 a. The first electrode2 and second electrode 3 are interconnected with the liquid in thecavity 1 e. Then the first electrode 2 and second electrode 3 areconnected with the pulse power supply. Electrification produces anelectric field within the shock tube 20, causing the cell membranes topossess certain permeability, so that the target material in the liquidsample can enter the cells. When the stopple 4 is fixed to the endportion of the tube 1, a compressive deformation is generated in theelastic piece, to avoid the formation of gaps between the secondelectrode 3 and the opening 1 a, improving the sealing performancebetween the second electrode 3 and the end surface of the opening 1 a,thereby preventing air from entering the liquid sample in the cavity 1e. In addition, when the stopple 4 becomes slightly uptilted, theelastic piece can also make certain deformation recovery, to ensure thesecond electrode 3 to remain closely abutting with the end surface atthe edge of opening 1 a, so that still no air bubble will be generatedin liquid sample in the cavity 1 e when there is some operationdeviation during sample loading by the experimenter, effectively improvesealing performance between the second electrode 3 and the opening 1 a,thereby inhibiting ambient air from entering the cavity 1 e when loadingliquid sample.

In one embodiment, the tube 1 and stopple 4 are made of an insulatingmaterial. The first electrode 2 and second electrode 3 are made of anelectrically conductive material. The first electrode 2 may either bedirectly fixed to the tube 1, or may be installed inside a stopple 4, aswith the second electrode 3 before being used to seal the cavity 1 e oftube 1. The elastic piece is an elastic piece 5 made of rubber andplastic materials. The stopple 4 comprises the pipe having a firstthrough-hole 41. The second electrode 3 is plug-in to the firstthrough-hole 41. The second electrode 3 comprises a rod 31 and a cap 32which is fixedly connected to one end of the rod 31. The other end ofthe rod 31 can be electrically connected with the exterior via anopening of the stopple 4. The elastic piece 5 is socket-connected on theouter side surface of rod 31. The outer end of the stopple 4 has aretaining edge 42 radially extended inward along first through-hole 41.The outer end surface of the elastic piece 5 abuts against the retainingedge 42, and the inner end surface of the elastic piece 5 abuts againstthe cap 32. Rubber and plastic materials include plastics, rubber,silicone and the like. When the stopple 4 is fixed to the end of tube 1,the second electrode 3 is well-matched with end surface of the edge ofopening 1 a of cavity 1 e of tube 1. The elastic piece 5 generates acompressive deformation to improve sealing effect of the secondelectrode 3 with end surface of the edge of opening 1 a. The rod 31 canpass through the retaining edge 42 and extends to the exterior of thestopple 4 to facilitate the electrification of second electrode 3. Ofcourse the second electrode 3 may also not extend to the exterior of thestopple 4. The external electrical connection contact is in contact withthe end of second electrode 3 to achieve electrical connection. Theelastic piece 5 may be generally made into complete ring-shape and maybe an incomplete ring, as long as it is resilient and capable of beingplugged with the second electrode 3.

In one embodiment, the elastic piece 5 may be a separate elastic piece 5mounted in first through-hole 41 with an interference fit method, ormounted in first through-hole 41 by bonding or other methods. A firstretaining shoulder 33 is provided between the elastic piece 5 and thecap 32. The first retaining shoulder 33 may be made into ring-shape anddisposed on the same axis as elastic piece 5 and cap 32. The size ordiameter of the first retaining shoulder 33 is larger than the diameterof rod 31 and smaller than the diameter of cap 32. First retainingshoulder 33 may also have an incomplete ring shape or other shapes. Itssize or spatial dimension has to be larger than the diameter of rod 31and smaller than the diameter of cap 32. The first retaining shoulder 33separates the cap 32 from the elastic piece 5, causing the cap 32, incompressing the elastic piece 5, has to apply stress through the firstretaining shoulder 33. The diameter or size of first retaining shoulder33 is smaller than the cap 32 and elastic piece 5, thereby producingrelatively greater pressure on a small contact area, prompting easydeformation and displacement of elastic piece 5. When the stopple 4 isfixed in the positioning structure, the second electrode 3 iswell-matched with end surface of the opening 1 a. The elastic piece 5 isin compressed state under pressure from the second electrode 3. Pressureis generated by this compressive deformation and exerted to end surfaceof opening 1 a at end of tube 1 to improve sealing performance, and whenthe stopple 4 is slightly uptilted, a certain deformation recovery willbe generated to maintain the pressing of second electrode 3 against theend surface of opening 1 a at end of tube 1.

The first retaining shoulder 33 is a separate component. The firstretaining shoulder 33 is socket-fitted on the rod 31 between the elasticpiece 5 and the cap 32. Its material may be an insulator ornon-insulator. The outer side surface of elastic piece 5 is well-matchedwith the inner wall of first through-hole 41 and forms a seal. The innerside surface of elastic piece 5 is well-matched with the outer sidesurface of rod 31 and forms a seal.

The first rib 1 d and second rib 43 may be of a complete annular-shapeor discontinuous annular shape. A snap-connection effect can be achievedin both cases. The protrusions of first rib 1 d and second rib 43 maynot be obvious. A stopple 4 of size slightly larger than the internalsize of the connecting tube 1 b is used to insert into the tube 1portion, to achieve the purpose of positioning by interference fitmethod. The stopple 4 is snap-connected with the connecting tube 1 b,making both connection and separation of the two very easy, to enhancethe convenience in liquid injection and pipetting after the completionof electroporation. Of course the threaded connection method may also beused. While using threaded connection, the stopple 4 can be fixed to theconnecting tube 1 b by rotating it. As alternative case, the positioningstructure may be a first strike disposed on the stopple 4 and a firstlatch disposed on tube 1 which can snap-connect with the first strike.

As shown in FIG. 2, in one embodiment, the end surface at edge of theopening 1 a of tube 1 has an annular groove 1 f. The cavity 1 e isfilled up with a liquid sample until a bulged surface is formed on theopening 1 a. Then the second electrode 3 is in contact with the bulgedliquid surface and presses downward to seal the opening 1 a. The excessliquid of bulged surface is squeezed and flows into the annular groove 1f, without affecting the cell electroporation process in liquid samplein the cavity 1 e.

As shown in FIG. 2, the cavity 1 e of tube 1 is provided with an ionconductive layer 1 g. The bottom layer surface of the ion conductivelayer 1 g is in contact with a first electrode 2. The upper layersurface of the ion conductive layer 1 g is capable of contacting withthe target liquid sample. The cell sample is separated from directcontact with the first electrode 2 by ion conductive layer 1 g, so as toavoid direct damage to the cell sample by electrochemical reaction nearthe first electrode 2. The ion conductive layer 1 g contains componentsof a soluble salt as the ion source, which infiltrates the salt solutionand forms conductive ions.

Embodiment 2

As shown in FIG. 4, the present embodiment is substantially the same asEmbodiment 1, except the following. The first retaining shoulder 33forms an integral body with the cap 32 and rod 31. The inner end surfaceof elastic piece 5 abuts against the end surface of first retainingshoulder 33. When the rod 31 is plugged inelastic piece 5, the cap 32and elastic piece 5 are separated by and mutually exert stresses throughfirst retaining shoulder 33. The first retaining shoulder 33 may be inannular shape, discontinuous annular shape, polygonal shape or othershapes. Its size or diameter is larger than the diameter of rod 31 andsmaller than the diameter of cap 32.

Embodiment 3

As shown in FIG. 5, the present embodiment is substantially the same asEmbodiment 1 or Embodiment 2, except the following. The first retainingshoulder 33 is fixedly arranged on the elastic piece 5 or the firstretaining shoulder 33 forms an integral body with the elastic piece 5.The first retaining shoulder 33 abuts against the cap 32. The firstretaining shoulder 33 may be in annular shape, discontinuous annularshape, polygonal shape or other shapes. Its size or diameter is largerthan the diameter of rod 31 and smaller than the diameter of cap 32.

Embodiment 4

As shown in FIG. 7, the present embodiment is substantially the same asEmbodiment 1, except the following. An alternative solution is providedfor elastic piece in the present embodiment. The elastic piece is aresilient retaining edge elastic piece 18 extended inward along firstthrough-hole 41 on inner wall of the first through-hole 41. Theretaining edge elastic piece 18 abuts against the outer side surface ofthe rod 31 and forms a seal. A second retaining shoulder 34 is alsoprovided between the retaining edge elastic piece 18 and the cap 32. Thesecond retaining shoulder 34 is disposed separately. The secondretaining shoulder 34 may be fabricated into ring shape and disposed onthe same axis as the retaining edge elastic piece 18 and the cap 32. Thediameter of the second retaining shoulder 34 is larger than the diameterof rod 31 and smaller than the diameter of cap 32. The second retainingshoulder 34 may also be in incomplete ring shape or other shapes. Itssize or spatial dimension is larger than the diameter of rod 31 andsmaller than the diameter of cap 32. The material of retaining edgeelastic piece 18 is the same as stopple 4. The outer side forms anintegral body with inner wall of the body of the stopple 4, and anopening is formed in the center. The rod 31 of second electrode 3 isplug-in to the opening of retaining edge elastic piece 18 byinterference fit or bonding method. Due to precision requirement of thebody of shock tube 20, it is generally necessary to be manufactured withcertain strength to prevent deformation. As an elastic piece, theretaining edge elastic piece 18, which forms an integral body with thestopple 4, may use the strength reduction design there to gainflexibility, such as designing a thinner portion than the otherportions, so that it is more prone to pressure deformation. Theretaining edge elastic piece 18 may generally be made into a completering shape, or it may be an incomplete ring in shape, all acceptable aslong as it is flexible and can be plugged with the second electrode 3.

Embodiment 5

As shown in FIG. 8, the present embodiment is substantially the same asEmbodiment 4, except the following. The second retaining shoulder 34forms an integral body with the cap 32 and rod 31 in the presentembodiment. The inner end surface of the retaining edge elastic piece 18abuts against the end surface of the second retaining shoulder 34. Thesecond retaining shoulder 34 may be in annular shape, discontinuousannular shape, polygonal shape or other shapes. Its size or diameter islarger than the diameter of rod 31 and smaller than the diameter of cap32.

Embodiment 6

As shown in FIG. 9, the present embodiment is substantially the same asEmbodiment 4 or Embodiment 5, except the following. The second retainingshoulder 34 forms an integral body with the retaining edge elastic piece18 in the present embodiment. The second retaining shoulder 34 abutsagainst the cap 32. The second retaining shoulder 34 may be in annularshape, discontinuous annular shape, polygonal shape or other shapes. Itssize or diameter is larger than the diameter of rod 31 and smaller thanthe diameter of cap 32.

Embodiment 7

As shown in FIG. 10, the present embodiment is substantially the same asEmbodiment 1, except the following. As a solution for third type ofelastic piece, the elastic piece in the present embodiment is acompression spring 6. The stopple 4 comprises a pipe having a firstthrough-hole 41. The second electrode 3 is disposed in the firstthrough-hole 41. The second electrode 3 comprises a rod 31 and a cap 32.One end of the rod 31 is fixedly connected with the cap 32. The otherend of the rod 31 can be electrically connected with the exterior via anopening of the stopple 4. The compression spring 6 is socket-connectedon the outer side surface of the rod 31. The outer end of the stopple 4has a retaining edge 42 radially extended inward along the firstthrough-hole 41. The outer end surface of the compression spring 6 abutsagainst the retaining edge 42, and the inner end surface of thecompression spring 6 abuts against the cap 32. When the stopple 4 isfixed to the end part of tube 1, the compression spring 6 can generate adeformation compression to improve the sealing performance between thesecond electrode 3 and the end part of tube 1 at the edge of opening 1a.

Embodiment 8

As shown in FIG. 11 to FIG. 15, the present embodiment provides a cellelectroporation device with a shock tube 20, wherein the cellelectroporation device comprises a housing 7. The housing 7 is disposedwith a fixing base 8 inside. The fixing base 8 is provided with a socket821. The cell electroporation device also comprises a shock tube 20which is plug-in to the socket 821. The shock tube 20 comprises a tube1, a first electrode 2, a second electrode 3 and a stopple 4, whereinthe tube 1 is internally provided with a cavity 1 e for accommodating atarget liquid sample. The first electrode 2 is arranged at one end ofthe tube 1, and the other end of tube 1 is provided with an opening 1 ainterconnected with the cavity 1 e. The working part of the firstelectrode 2 is interconnected with the cavity 1 e. The edge of theopening 1 a has an annular end surface. The second electrode 3 isarranged in the stopple 4, and the outer end of the second electrode 3can be electrically connected with the exterior via an opening of thestopple 4. The inner end surface of the second electrode 3 can bewell-matched with the annular end surface of the edge of opening 1 a. Anelastic piece is arranged between the stopple 4 and the second electrode3. The outer side surface of elastic piece abuts against or connectswith the stopple 4, and inner side surface of the elastic piece abutsagainst the second electrode 3. The periphery of opening 1 a has apositioning structure which is capable of fixing the stopple 4 at theend portion of tube 1 generating a compressive deformation to theelastic piece. The inner end of the socket 821 has a first electrodeterminal 10 which can be electrically connected to the first electrode2. The housing 7 is provided with a cover 9 for covering the outer endof socket 821. The cover 9 is disposed with a second electrode terminal11 which can be electrically connected with the second electrode 3. Thehousing 7 is also provided with a power module 27 which is electricallyconnected to the first electrode terminal 10 and second electrodeterminal 11.

During operation, one embodiment of the cell electroporation device canbe filled up into the cavity 1 e of tube 1 with a liquid sample and thencovered with stopple 4. After the shock tube 20 is placed in the socket821, the cover 9 is closed, so the first electrode terminal 10 iselectrically connected to the first electrode 2, and the secondelectrode terminal 11 is electrically connected to the second electrode3, and the pulse power is turned on to supply electricity, producing anelectric field within the shock tube 20, enabling the injection ofextracellular substances into the cells. Since the stopple 4 is alsoprovided with an elastic piece for enhancing the action force betweenthe second electrode 3 and the end surface of opening 1 a, thusinhibiting gap formation between the second electrode 3 and the opening1 a. In addition, when the stopple 4 becomes slightly uptilted, theelastic piece can also make certain deformation recovery, to ensure thesecond electrode 3 to remain closely abutting with the end portion oftube 1 at end surface of opening 1 a, thus inhibiting ambient air fromentering the cavity 1 e. Meanwhile, the internal generation of airbubbles by electrochemical reaction in the shock tube 20 duringelectroporation process can also be restrained. In summary, the shocktube 20 of the cell electroporation device can effectively improvesealing performance between the second electrode 3 and the end surfaceof opening 1 a, thus inhibiting ambient air from entering the cavity 1 eof the shock tube 20 and generates air bubbles and influence theelectroporation, during the electroporation preparation process, reducethe influence of air bubbles generated by electrochemical reaction onelectric current during the electroporation process, thereby improvingthe electroporation performance of the cell electroporation device.

As shown in FIGS. 11, 12, and 13, one embodiment of the fixing base 8comprises a seat 81 and a clamping cylinder 82. The socket 821 isdisposed inside the clamping cylinder 82. A silo 811 is provided in theseat 81. The clamping cylinder 82 is inserted in the silo 811 and bothare removable and interconnected. The bottom of the clamping cylinder 82abuts with the bottom of the silo 811. The top end of clamping cylinder82 is provided with at least one handle 822.

As shown in FIG. 12, one embodiment of the seat 81 contains also ahollow 12. The silo 811 has a second through-hole 13 at its bottom. Thetwo ends of the second through-hole 13 are connected with the socket 821and hollow 12 respectively. The hollow 12 is provided with a spring seat14 and a spring 15. The inner end of spring 15 is fixed to the springseat 14, and the outer end of spring 15 is connected to the inner end ofthe first electrode terminal 10. The outer end of the first electrodeterminal 10 can pass through the second through-hole 13 and inserted inthe socket 821. After the spring seat 14 and spring 15 are provided inthe design, when the socket 821 opening 1 a is closed by the cover 9,the first electrode 2 and second electrode 3 can be connected to thefirst electrode terminal 10 and second electrode terminal 11respectively. When the shock tube 20 is pressed by the cover 9, thespring 15 is compressed and a greater extra pressure is generated. Thispressure is exerted through the second electrode 3 to the opening 1 a ofcavity 1 e, enhancing the sealing performance of second electrode 3 andopening 1 a of cavity 1 e. During the cell electroporation process, dueto the electrochemical reaction, the electrolysis process will producesome air bubbles. When the pressure between the second electrode 3 andthe opening 1 a of cavity 1 e becomes higher, these electrochemical airbubbles will be compressed and its influence to the distribution ofelectric current in the electroporation process will be reduced, therebyincreasing cell electroporation effect. After the completion of cellelectroporation, when the cover 9 is opened, the shock tube 20 may popup partially from the socket 821 under the action of the spring 15,making it convenient to pick it up.

The inner end of the cover 9 is hinged to the housing 7. Outer end ofthe cover 9 is provided with a second latch 16. The housing 7 is alsoprovided with a second strike 17 which can snap-connect with the secondlatch 16. The clamping cylinder 82 and cover 9 are made of a materialwith light transmittance greater than 50%. The accessory of seat 81 isinternally provided with a sensor 29 for detecting the displacementchange of shock tube 20. The housing 7 is provided inside with a microcontrol unit 25. The micro control unit 25 is electrically connectedwith the sensor 29. The seat 81 is also provided inside with anindicator lamp 28 which is electrically connected with micro controlunit 25. The indicator lamp 28 is also connected with the power module27. In addition to the function of indicating the connection status ofshock tube 20, the indicator lamp 28 can also serve the function ofillumination. A brighter light source such as LED light can be used toilluminate the shock tube 20. The sensor 29 can be a mechanical triggerswitch. The switch will be triggered by its linkage bar whendisplacement of first electrode terminal 10 occurs. The sensor 29 canalso be a photoelectric switch. The photoelectric switch will betriggered by an affected optical path when displacement of firstelectrode terminal 10 occurs. The sensor 29 can also be a Hall switchetc., triggered when displacement of the shock tube 20 or firstelectrode terminal 10 occurs.

The indicator lamp 28 is mounted on housing 7 near the shock tube 20socket 821, providing lights to illuminate the shock tube 20 nearby.Alternatively, the indicator lamp 28 can also be mounted on the fixingbase 8. A transverse through-hole may be provided on the fixing base 8to install the indicator lamp 28. The clamping cylinder 28 can be madeof a transparent material. The indicator lamp 28 on the fixing base 8may be used to illuminate the shock tube 20 laterally through theclamping cylinder 82, achieving a clearer visual effect. The housing 7is provided with a display screen 26. The housing 7 is internallyprovided with a sampler 24. The micro control unit 25 is electricallyconnected with display screen 26 and power module 27. The sampler 24 iselectrically connected with shock tube 20 and micro control unit 25respectively. Power supply module 27 can generate electric pulsesrequired in cell electroporation. The display screen 26 is used fordisplaying instrumental and experimental information as well as displaythe experiment operation interface. The micro control unit 25 cancontrol the power module 27 and display screen 26. The micro controlunit 25 includes a programmable single-chip microcomputer and othermicroprocessors etc. The sampler 24 can collect electrical signals incell electroporation process, including voltage or current signals. Thesampler 24 includes resistors and other electronic components.Electrical signals are being processed via the micro control unit 25,and related parameters can be displayed in the form of data values orwave curves on the display screen 26.

Embodiment 9

As shown in FIGS. 16 and 17, one embodiment of the shock tube comprisesa tube 1 and a stopple 4. The stopple 4 is connected to the tube 1 via aflexible link 30. The tube 1 is internally provided with a cavity 1 efor accommodating a target liquid sample. The first electrode 2 which isconnected with cavity 1 e is arranged at one end or middle part of thetube 1, and the other end of the tube 1 is provided with an opening 1 ainterconnected with the cavity 1 e. The end surface at edge of theopening 1 a has an annular groove 1 f. The second electrode 3 isarranged in the stopple 4, and the outer end of the second electrode 3can be electrically connected with the exterior via an opening of thestopple 4. The second electrode 3 is slidably connected to the stopple4. The inner end surface of the second electrode 3 can be well-matchedwith the annular end surface of the edge of opening 1 a, characterizedin that, the stopple 4 comprises a pipe 45 having a first through-hole41 and a tubular mounting seat 44 located in the pipe 45. The secondelectrode 3 is slidably connected on the mounting seat 44 and an annularelastic piece 5 is socket-fitted outside the mounting seat 44. Theheight of elastic piece 5 is greater than the height of mounting seat44. The height of pipe 45 of the stopple 4 is greater than the height ofthe elastic piece 5. When the stopple 4 is fixed to the end portion oftube 1, the elastic piece 5 generates a compressive deformation, causingupper end surface of elastic piece 5 abuts against the stopple 4 andlower end surface of elastic piece 5 abuts against the second electrode3. During operation, the shock tube can be filled up into the cavity 1 efrom opening 1 a of tube 1 with a liquid sample comprising cells andmaterials to be injected into the cells, and then the stopple 4 issecured to the end of tube 1. Inner end surface of second electrode 3 iswell-matched with the annular end surface at the edge of tube 1 opening1 a. The inner ends of first electrode 2 and second electrode 3 areinterconnected with the liquid in the cavity 1 e, and the outer ends offirst electrode 2 and second electrode 3 can be electrically connectedwith the exterior, so the first electrode 2 and second electrode 3 areconnected with the pulse power supply. Electrification produces anelectric field within the cavity 1 e of shock tube, causing the cellmembranes to possess certain permeability, so that the target materialin the liquid sample can enter the cells. In the present technicalsolution, when the stopple 4 is fixed to the end portion of the tube 1,the elastic piece 5 is positioned between the pipe 45 of the stopple 4and the mounting seat 44, and the two ends of the elastic piece 5 abutagainst the stopple 4 and second electrode 3 respectively. The elasticpiece 5 generates compressive deformation, so that the elastic piece 5forms a seal with the stopple 4 and second electrode 3, preventingoccurrence of gaps between the second electrode 3 and the opening 1 a oftube 1, and inhibiting air from entering the liquid sample in cavity 1e. Further, when the stopple 4 becomes slightly uptilted, the elasticpiece 5 can also make certain deformation recovery, to ensure the secondelectrode 3 to remain closely abutting with the end surface of opening 1a edge, so that still no air bubble will be generated in liquid samplein the cavity 1 e when there is some operation deviation during sampleloading by the experimenter. In summary, the technical solution caneffectively improve sealing performance between second electrode 3 andopening 1 a, thus inhibiting ambient air from entering the cavity 1 ewhen loading liquid sample. Since the elastic piece 5 is positionedbetween the pipe 45 of the stopple 4 and mounting seat 44, and its upperand lower ends abut against the stopple 4 and second electrode 3respectively, therefore no falling off will occur.

The tube 1 and stopple 4 in one embodiment are made of an insulatingmaterial. The first electrode 2 and second electrode 3 are made of anelectrically conductive material, which is a part of the prior art, andthe specific material being used are not the subject of thisSpecification. In addition, the first electrode 2 may either be directlyfixed to the tube 1, or may be installed inside the stopple 4, as withthe second electrode 3 before being used to seal the cavity 1 e of tube1.

As shown in FIG. 17, the inner side surface of one embodiment of elasticpiece 5 is in contact with the outer side surface of mounting seat 44.The inner side surface of elastic piece 5 is in contact and abutsagainst the stopple 4, forming a multi-face seal connection. The sealingperformance is further enhanced by the formation of seal connectionbetween the lower end surface of elastic piece 5 and second electrode 3.The rim 31 a is cone shape. Outer side surface of the rim 31 a has afirst guiding surface 31 b obliquely extended towards outer side surfacefrom end surface of rim 31 a. The inner side wall of the mounting seat44 is provided with a second guiding surface obliquely extended to innerside wall from end surface of the mounting seat 44. Through the guidingeffect of first guiding surface 31 b and second guiding surface, it ispossible to facilitate the installation and placement of the secondelectrode 3.

The periphery of the opening 1 a has a positioning structure which iscapable of fixing the stopple 4 at the end portion of tube 1 andgenerating a compressive deformation to the elastic piece 5. Thepositioning structure comprises a connecting tube 1 b which forms anintegral body with the end part of the tube 1. The connecting tube 1 bis provided with a chamber 1 c for the stopple 4 to plug-in. The chamberwall of the chamber 1 c has a first rib 1 d. The outer side surface ofthe stopple 4 has a second rib 43 which can snap-connect with first rib1 d. Through the positioning structure, the elastic piece 5 is deformedto further improve the sealing performance, while it is also possible toeffectively prevent the stopple 4 from falling off the end of tube 1.The first rib 1 d and second rib 43 may be of a complete annular-shapeor discontinuous annular shape or even non-annular shape. Asnap-connection effect can be achieved in all cases. The protrusions offirst rib 1 d and second rib 43 may not be obvious. A stopple 4 of sizeslightly larger than the internal size of the connecting tube 1 b isused to insert into the tube 1 portion, to achieve the purpose ofpositioning by interference fit method. The stopple 4 is snap-connectedwith the connecting tube 1 b, making both connection and separation ofthe two very easy, to enhance the convenience in liquid injection andpipetting after the completion of electroporation. Of course thethreaded connection method may also be used. While using threadedconnection, the stopple 4 can be fixed to the connecting tube 1 b byrotating it.

The second electrode 3 comprises a rod 31 and a cap 32. One end of therod 31 is fixedly connected with cap 32. The other end of the rod 31 canbe electrically connected with the exterior via an opening of thestopple 4. Furthermore, that end also has a rim 31 a, which is extendedradially along rod 31. The opening of the stopple 4 has an abutmentsurface 46 abutting against the rim 31 a. The rim 31 a is capable of,under deformation of the mounting seat 44 due to external load, andpassing easily through the mounting seat 44, and then abuts against theabutment surface 46 at opening 1 a portion of the stopple 4. After themounting seat 44 has recovered from the deformation, the rim 31 a incoordination with the abutment surface 46 to forms a limiting structure,which is capable of effectively preventing the second electrode 3 fromfalling off. There is a gap between outer side surface of the elasticpiece 5 and inner side wall of the pipe 45 of the stopple 4. When thestopple 4 is fixed to the end of tube 1, lower end surface of elasticpiece 5 abuts against upper end surface of the cap 32. There is a gapbetween outer circumferential surface of the cap 32 and inner side wallsof pipe 45 of the stopple 4 too. The retaining of gaps at these twoplaces can provide a certain amount of space for deformation of elasticpiece 5, so that the automatic adjustment of gap closure between thestopple 4 and second electrode 3 is achieved by using the recovery forceof elastic piece 5.

Embodiment 10

As shown in FIG. 18, the present embodiment is substantially the same asEmbodiment 9, except the following. In the present embodiment, thestopple 4 comprises a pipe 45 having a first through-hole 41. The rod 31is inserted into the first through-hole 41. The pipe 45 is internallyprovided with a tubular mounting seat 44. The second electrode 3 isslidably connected on the mounting seat 44. The wall thickness oftubular mounting seat 44 becomes gradually thinner from top to bottom,so that the lower end portion has relatively better flexibility. Theelastic piece 5 is the resilient part at lower end of the mounting seat44. The joint of the rod 31 and cap 32 is provided with a slope 31 cabutting against the elastic piece. After the slope 31 c of the rod 31is inserted into the mounting seat 44, the elastic piece 5 on themounting seat 44 is elastically deformed to improve sealing performanceand resiliency.

Embodiment 11

As shown in FIG. 19, the present embodiment is substantially the same asEmbodiment 9, except the following. The limiting structure of thepresent embodiment comprises an annular bulge 45 b on inner wall of pipe45. The cap 32 is disk shape, and outer diameter of the cap 32 is largerthan inner diameter of the annular bulge 45 b. The cap 32 can passthrough the annular bulge 45 b in such a way that the lower end surfaceof cap 32 is above the upper side surface of the annular bulge 45 b.After the annular bulge 45 b on pipe 45 is deformed under externalcompression, the cap 32 can pass smoothly through the inner hole ofannular bulge 45 b. After the annular bulge 45 b has recovered from thedeformation, the outer end surface of cap 32 abuts against the upperside surface of annular bulge 45 b and maintains the limitation,effectively preventing the second electrode 3 from falling off.

Embodiment 12

As shown in FIGS. 16 and 20, the present embodiment is substantially thesame as Embodiments 1 to 11, except the following. The first electrode 2is arranged at middle of the tube 1 and forms a seal with the tube 1.The first electrode 2 is acting as a divide in the tube 1. A part of itis provided with a cavity 1 e for accommodating a target liquid sample.The other part of tube 1 is the extension segment 1 h, which is capableof preventing the first electrode 2 and second electrode 3 fromgenerating a high voltage arc on the outer side of the tube 1.

During operation, one embodiment of the shock tube can be filled up intothe cavity 1 e from opening 1 a of tube 1 with a liquid samplecomprising cells and materials to be injected into the cells, then thestopple 4 is secured to the end of tube 1, and inner end surface ofsecond electrode 3 is well-matched with the annular end surface at theedge of opening 1 a of tube 1. Both the first electrode 2 and secondelectrode 3 are interconnected with the liquid in the cavity 1 e, and anelectrode terminal with insulation cover can be extended into theextension segment 1 h of tube 1 and electrically connected with firstelectrode 2, and outer end of second electrode 3 can be electricallyconnected with the exterior via an opening of the stopple 4, so thefirst electrode 2 and second electrode 3 are connected with the pulsepower supply. Electrification produces an electric field within thecavity 1 e of shock tube, causing the cell membranes to possess certainpermeability, so that the target material in the liquid sample can enterthe cells. In the present technical solution, the part of tube 1 belowfirst electrode 2 is the extension segment 1 h, which is capable ofpreventing the first electrode 2 and second electrode 3 from generatinga high voltage arc on the outer side of the tube 1. The extensionsegment has good insulation performance. For the first electrode 2 andsecond electrode 3 to produce a high voltage arc outside the tube 1, thegap distance for voltage breakdown has been increased by at least thelength of extension segment 1 h or twice the length of extension segment1 h, since the arc has to bypass the extension segment 1 h. The voltagebreakdown gap distance between the first electrode 2 and secondelectrode 3 is extended greatly by the provision of extension segment 1h. Even if a very high voltage is applied, it can effectively preventthe breakdown between first electrode 2 and second electrode 3 in theambient air of tube 1, thus ensuring the electric current to achieveelectroporation to the target liquid sample in cavity 1 e. In addition,the extension segment 1 h is serving as a handle too, for convenience inplacement and installation of the shock tube.

The lengths of extension segment 1 h play a critical role. For example,when the length of extension segment 1 h is greater than the length ofcavity 1 e, and outer side of electrode terminal is insulated, lengthgreater than the length of cavity 1 e, while the length of extensionsegment 1 h is greater than length of cavity 1 e, the air breakdown pathdistance between the first electrode 2 and second electrode 3 outsidethe tube 1 is at least three times the length of cavity 1 e, hence thefirst electrode 2 and second electrode 3 are almost impossible toproduce a high voltage arc outside the tube 1. The tube 1 is made ofplastic material, and the wall thickness of tube 1 in extension segment1 h is smaller than the wall thickness of tube in the cavity 1 e. Thewall thickness of tube in the cavity 1 e is relatively larger to preventthe high voltage breakdown between the first electrode 2 and the secondelectrode 3. In the meantime, the wall thickness of tube in extensionsegment 1 h is less than the wall thickness of tube in the cavity 1 e tofacilitate the insertion of first electrode 2 from the extension segment1 h into the tube 1 and installed in the middle of the tube 1, and alsofacilitates the insertion of electrode terminal into the extensionsegment 1 h of tube 1 to have electrical connection with the firstelectrode 2. The interior diameter of the tube 1 in extension segment 1h is greater than the interior diameter of the tube 1 in the cavity 1 eand forms a step 1 i in the tube 1. The first electrode 2 ismulti-segment cylindrical or conical in shape. The first electrode 2 hasa flange 21 and a peg 22 located at upper side of flange 21. Thecircumferential surface of flange 21 is snap-connected with the sidewall of tube hole on extension segment 1 h, and the end surface of theflange 21 is in contact with the step 1 i. The peg 22 is snap-connectedin the tube hole of the cavity 1 e. The step 1 i and flange 21coordinate with each other to play a role in positioning and limitation,and to increase contact area, to improve ease of installation whileensuring sealing performance and to prevent leakage of target liquidsample. The first electrode 2 at lower side of flange 21 is providedwith a contact part 23. The diameter of the contact part 23 is smallerthan diameter of flange 21, and there is a gap between the contact part23 and tube wall of extension segment 1 h of the tube 1. The contactpart 23 can also facilitate the handling, placement and installation ofthe first electrode 2. In addition, the length of the contact part 23 isshorter than the length of peg 22. The peg 22 has a longer length tofacilitate installation and fixation, as well as having a better contactwith the target liquid sample in cavity 1 e, conducting electricalcurrent and electric field to act on the cells in the target liquidsample. The length of the contact part is usually short, to prevent tooclose a distance from first electrode 2 to lower end of extensionsegment 1 h, which may induce voltage arc, bypassing the extensionsegment 1 h.

Further, an annular bulge is provided on the peg 22 of first electrode 2or the flange 21 along the circumference of the first electrode 2. Theannular bulge forms a tight fit seal with the inner wall of the cavity 1e. The provision of seal between annular bulge and inner wall of cavity1 e can facilitate installation and reducing resistance during the firstelectrode 2 placement. As an even advanced solution, if the peg 22 formsa tight fit seal with the inner wall of the cavity 1 e, the outer sidesurface of the flange 21 and the tube wall of extension segment 1 h mayleave some gaps for easy installation.

The tube 1 and stopple 4 in the present embodiment are made of aninsulation material. The first electrode 2 and second electrode 3 aremade of an electrically conductive material, which is a part of theprior art, and the specific material being used are not the subject ofthis Specification. The length of extension segment 1 h in the presentembodiment is ⅓ ˜⅔ of the total length of tube 1.

The first retaining shoulder 33 and second retaining shoulder 34 in theabove embodiment may be of a complete annular-shape or composed ofseveral arcuate segments. The simple conversion of these structuralshapes is substantially identical to the present technical solution.

The description of the preferred embodiments thereof serves only as anillustration of the scope of the invention. It will be understood bythose skilled in the art that various changes or supplements in form anddetails may be made therein without departing from the scope of theinvention as defined by the appended claims.

While the present invention has been described in detail and cited withreference to specific embodiments thereof, it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit and scope of the invention.

LIST OF REFERENCE NUMERALS

-   1 Tube-   1 a Opening-   1 b Connecting tube-   1 c Chamber-   1 d First rib-   1 e Cavity-   1 f Annular groove-   1 g Ion conductive layer-   1 h Extension segment-   1 i Step-   2 First electrode-   20 Shock tube-   3 Second electrode-   4 Stopple-   5 Elastic piece-   6 Compression spring-   7 Housing-   8 Fixing base-   9 Cover-   10 First electrode terminal-   11 Second electrode terminal-   12 Hollow-   13 Second through-hole-   14 Spring seat-   15 Spring-   16 Second latch-   17 Second strike-   18 Retaining edge elastic piece-   21 Flange-   22 Peg-   23 Contact part-   24 Sampler-   25 Micro control unit-   26 Display screen-   27 Power module-   28 Indicator lamp-   29 Sensor-   30 Flexible link-   31 Rod-   31 a Rim-   31 b First guiding surface-   31 c Slope-   32 Cap-   33 First retaining shoulder-   34 Second retaining shoulder-   41 First through-hole-   42 Retaining edge-   43 Second rib-   44 Mounting seat-   45 Pipe-   45 a Third guiding surface-   45 b Annular bulge-   46 Abutment surface-   81 Seat-   811 Silo-   82 Clamping cylinder-   821 Socket-   822 Handle

What is claimed is:
 1. A shock tube (20), comprising: a tube (1); acavity (1 e) inside the tube (1), the cavity (1 e) capable ofaccommodating a target liquid sample; a first electrode (2) arranged ata first end of the tube (1), a working part of the first electrode (2)being interconnected with the cavity (1 e); an opening (1 a) at a secondend of the tube (1), the opening (1 a) interconnected with the cavity (1e), an edge of the opening (1 a) having an annular end surface; astopple (4); a second electrode (3) arranged in the stopple (4), anouter end of the second electrode (3) capable of being electricallyconnected with an exterior via an opening of the stopple (4), an innerend surface of the second electrode (3) capable of being well-matchedwith the annular end surface of the edge of the opening (1 a); and anelastic connection in between the second electrode (3) and the stopple(4); wherein a periphery of the opening (1 a) has a positioningstructure capable of fixing the stopple (4) at an end of tube (1) andrendering the second electrode (3) under elastic stress.
 2. The shocktube (20) of claim 1, further comprising: a pipe (45) of the stopple(4), the pipe (45) having a first through-hole (41); a cap (32) of thesecond electrode (3); a rod (31) of the second electrode (3), a firstend of the rod (31) fixedly connected with the cap (32), a second end ofthe rod (31) capable of being electrically connected with the exteriorvia an opening of the stopple (4); wherein the second electrode (3) isdisposed in the first through-hole (41).
 3. The shock tube (20) of claim2, further comprising: a first retaining shoulder (33) provided betweenthe elastic piece (5) and the cap (32); wherein a size of the firstretaining shoulder (33) is larger than a diameter of rod (31) andsmaller than a diameter of cap (32).
 4. The shock tube (20) of claim 3,wherein the first retaining shoulder (33) is fixedly arranged on the cap(32), and forms an integral body with the cap (32) and the rod (31); andwherein an inner end surface of the elastic piece (5) abuts against anend surface of the first retaining shoulder (33).
 5. The shock tube (20)of claim 1, wherein the elastic piece (5) is a resilient retaining edgeelastic piece (18) extended inward along the first through-hole (41) onan inner wall of the first through-hole (41); and wherein when thestopple (4) is fixed to an end of the pipe (1), the retaining edgeelastic piece (18) generates deformation to press the second electrode(3) against the opening (1 a).
 6. The shock tube (20) of claim 1,wherein the elastic piece (5) is a compression spring (6); and whereinwhen the stopple (4) is fixed to an end of the pipe (1), the compressionspring (6) generates deformation to press the second electrode (3)against the opening (1 a).
 7. The shock tube (20) of claim 1, furthercomprising: a connecting tube (1 b) of the positioning structure, theconnecting tube (1 b) forming an integral body with an end part of thetube (1); a chamber (1 c) of the connecting tube (1 b), the chamber (1c) capable of allowing the stopple (4) to plug-in; a chamber wall of thechamber (1 c), the chamber wall having a first rib (1 d); and an outerside surface of the stopple (4) having a second rib (43), the second rib(43) capable of snap-connecting with first rib (1 d).
 8. The shock tube(20) of claim 1, wherein an end surface at edge of the opening (1 a) hasan annular groove (10.
 9. The shock tube (20) of claim 1, wherein thestopple (4) and the tube (1) is connected by a flexible link (30). 10.The shock tube (20) of claim 1, wherein the stopple (4) and an outerside of the elastic piece (5) are well-matched and form a seal; andwherein an inner side of the elastic piece (5) and an outer side surfaceof the second electrode (3) are well-matched and form a seal.
 11. Theshock tube (20) of claim 1, wherein the cavity (1 e) of tube (1) isprovided with an ion conductive layer (1 g); wherein a bottom layersurface of the ion conductive layer (1 g) is in contact with the firstelectrode (2); and wherein an upper layer surface of the ion conductivelayer (1 g) is capable of contacting with the target liquid sample. 12.The shock tube of claim 1, further comprising: an elastic piece (5)inside the stopple (4); wherein when the stopple (4) is fixed to an endof the pipe (1), the elastic piece (5) generates compression deformationto press the second electrode (3) against the opening (1 a).
 13. A shocktube (20), comprising: a tube (1); a cavity (1 e) inside the tube (1),the cavity (1 e) capable of accommodating a target liquid sample; afirst electrode (2) arranged at a first end of the tube (1) or at amiddle of the tube (1); an opening (1 a) at a second end of the tube(1), the opening (1 a) interconnected with the cavity (1 e); a stopple(4); a second electrode (3) arranged in the stopple (4); an elasticconnection in between the second electrode (3) and the stopple (4); arod (31) of the second electrode (3), the rod (31) inserted in thestopple (4) and slidably connected to the stopple (4); a cap (32) of thesecond electrode (3), the cap (32) fixedly connected to an inner end ofthe rod (31); an edge of the opening (1 a) having an annular endsurface, the edge of the opening (1 a) capable of being well-matchedwith an outer end surface of the cap (32); and a limiting structureprovided between the second electrode (3) and the stopple (4), thelimiting structure capable of preventing separation of the rod (31) fromthe stopple (4).
 14. The shock tube (20) of claim 13, furthercomprising: a rim (31 a) of the limiting structure, the rim (31 a) beingon an outer end of the rod (31), the rim (31 a) radially extending fromthe rod (31); wherein a radial size of the rim (31 a) is slightly largerthan a diameter of the stopple opening; and wherein the rim (31 a) iscapable of pressing the stopple (4) under external force generatingdeformation, causing the stopple (4) to pass out of the stopple opening.